Robust sensorless control of high speed PMSM drives under low carrier ratios and parameter uncertainties

Operating high-speed Permanent Magnet Synchronous Motor (PMSM) drives at low carrier-to-fundamental frequency (C/F) ratios is critical for improving system efficiency, but it severely degrades the stability and performance of conventional sensorless control schemes. This paper addresses this critical system-level challenge. To overcome these limitations, a robust sensorless control strategy based on Active Disturbance Rejection Control (ADRC) is proposed, which enhances system resilience by actively estimating and compensating for total disturbances arising from parameter uncertainties and unmodeled dynamics. To make this advanced yet computationally intensive algorithm feasible for practical implementation, a high-fidelity hybrid (HY) discretization method is developed. This scheme achieves RK4-level accuracy for critical nonlinear dynamics while reducing the computational load by 30%. Subsequently, a systematic stability analysis is conducted to delineate the performance boundaries of conventional techniques and theoretically validate the superior stability of the proposed HY-discretized ADRC framework in the low C/F ratio domain. The proposed strategy's effectiveness is comprehensively validated on a 100-kW, 20,000 r/min industrial PMSM platform. Experimental results demonstrate stable, high-performance operation at C/F ratios as low as 6 and showcase superior robustness against significant parameter mismatches, confirming its viability for demanding drive systems.